For a long time, many people have sought to modify the color of their skin, of their eyelashes or of their hair, for example, to mask their grey hair. To do this, several technologies have been developed.
It is known to dye human keratin fibers, such as the hair, with dyeing compositions containing oxidation dye precursors, generally called oxidation bases. These oxidation bases are colorless or slightly colored compounds which, when combined with oxidizing agents, give rise, through a process of oxidative condensation, to colored compounds. These colored compounds are insoluble and are trapped inside the hair fiber.
It is also known that it is possible to vary the shades obtained with these oxidation bases by combining them with couplers or color modifiers. The variety of molecules used at the level of the oxidation bases and the couplers allows a rich palette of colors to be obtained.
The colors obtained may exhibit good fastness to shampoo. However, the oxidation reaction occurs with the aid of oxidizing agents such as hydrogen peroxide in a basic medium. These oxidizing agents attack the keratin of the hair, such that the cosmetic and mechanical properties of the hair can deteriorate considerably in the event of repeated dyeing.
It is also known to dye human keratin fibers by direct dyeing, which comprises applying to the keratin fibers direct dyes which are colored and dyeing molecules having affinity for the fibers. There may be mentioned, by way of examples of direct dyes which are conventionally used, nitro dyes, benzene dyes, anthraquinone dyes, nitropyridine dyes, azo dyes, cationic azo dyes, xanthene dyes, acridine dyes, azine dyes or dyes of the triarylmethane type or natural dyes.
Other method(s) exist for dyeing keratin materials using indandiones such as 1,2-indandiones and 1,3-indandiones. Such dyeing method(s) are, for example, described in the following Patent Applications: EP 1 010 419, EP 1 013 259, EP 1 300 134, WO 95/11001 and WO 99/18914. The colors thus obtained may be very chromatic and may not bring about chemical degradation of keratin, but at the same time may have the disadvantage of being only temporary or semipermanent, i.e., the colors may fade after only 4 to 5 shampooings.
A need therefore remains for compositions and methods for dyeing which allow good fastness to be obtained without involving the use of oxidizing agents which are likely to damage keratin materials.